Sidewall sampler



March 31, 1959 F. v. PORTER SIDEWALL'SAMPLER Original Filed Nov'. 2a, 1952 2 Sheets-Sheet l F76. la,

v. PORTER SIDEWALL SAMPLER March 31, 1959 2 Sheets-Sheet 2 Original Filed Nov. 28, 1952 FOBQ57 V P0275? INVENTOR.

flrmewa production may be expected. plurality of boreholes have been drilled, a map of the v United States Patent SIDEWALL SAMPLER Forrest Vernon Porter, Monterey Park, Calif., assignor, by mesne assignments, to Dresser Industries, Inc., Dallas, Tex., a corporation of Delaware Continuation of application Serial No. 322,963, Novem her 28, 1952. This application December 6, 1957, Serial No. 701,698

6 Claims. (Cl. 255-1.4)

This invention relates to the determination of the geological formations traversed by well boreholes, and more especially to methods and apparatus for obtaining samples from the side walls of previously drilled earth boreholes at any desired depth. 7

This application is a continuation of copending application Serial No. 322,963, filed November 28, 1952, now abandoned.

During the drilling of a well, the drilling operator is vitally interested in the type of geological strata through which the well borehole passes, since an accurate knowledge of the subsurface formations is necessary in order to determine when the well borehole has reached certain formations in which casing may be set or from which In a locality in which a contour of the formationsunderlying the entire locality may be obtained by correlating the information gleaned from samples taken from each well. Cores of large size are most desirable from a geological standpoint. A variety of methods for obtaining core samples in connection with the drilling operations are widely used, but are subject to certain disadvantages, particularly the mixing with the samples of well or drilling fluids, over prolonged periods of drilling which affects the accuracy of the samples obtained. Other widely used methods of core sampling independent of the main drilling operations provide for separate drilling of cores at an angle or laterally into the formations surrounding the borehole, or the obtaining of solid sample portions of the formations by methods employing the firing of hollow bullets or hollow core sam-' ling barrels or tubes into the surrounding formations to dislodge or intrap the samples. In these types of sam- .pling, difficult problems of satisfactorily collecting, the

samples and raising them to the top of the well are encountered.

The foregoing disadvantages of heretofore known methods of core sampling or sidewall sampling are overcome in the present invention, which is preferably, although not necessarily, accomplished bya conductor cable operated sampling tool, which is constructed and arranged to cut or break away from the borehole wall, tapered, conical or wedge-shaped samples of the formation, by the use of explosive cutting means of the shaped-charge type. The samples thus released from the formation are immediately collected in a suitable catcher or bailer-like portion of the apparatus, which is preferably closed after receiving the formation samples to shield the samples from washing contact with contaminating well fluids while the apparatus is withdrawn from the borehole.

It is accordingly an object of the invention to provide a novel side wall sampler for use in obtaining data rela-' tive to the strata surrounding well boreholes.

Another object of the invention is to provide an improved apparatus for cutting out are obtaining samples of the side wall formations of well boreholes, by the use ofshaped charge cutting apparatus'of novel design. A further object" of the invention is to provide core sampling apparatus as described, employing a novel meansfor collecting the samples obtained from the formations surrounding the borehole, at the same time the samples are cut or broken away from the formations.

Another object of the invention is to provide an improved conductor cable operated side wall sampler employing a shaped-charge cutting operation, and a retrieving apparatus for the samples which is conditioned and actuated by the explosive force of the shaped-charge during the cutting of the samples from the well formation.

The foregoing and other objects, advantages and fea-. tures of novelty of the invention will appear to be brought out more fully in the following specification, reference being had to the accompanying drawings, wherein like reference characters refer to like parts.

In the drawings:

Fig. 1a is a view in sectional elevationv of the upper portion of a side wall sampler embodying the invention;

Fig. 1b is a similar view showing the lower portion of the sampler;

Fig. 2 is an enlarged cross-sectional view taken along line 2-2 of Fig. lb;

Fig. 3 is a view similar to Fig. 1b, showing the apparatus after actuation.

Referring to the drawings, and especially to Figures 1a:

to 3, the side wall sampler of this invention comprises a hollow cylindrical or tubular body member 10 making at its upper end a threaded connection at 11 to a head member 12, which in turn makes threaded connection at 13 to a cable head 14. Anchored within the cable head 14 is a conductor cable 15 by means of which the tool is lowered into a well borehole from which side wall samhole, adjacent a portion of a stratum as illustrated at 20 from which a sample is to be obtained. A plurality of fluid flow pressure equalization ports 21 are formed through the Wall of the body member 10. In the upper portion thereof, and above apertures 21, a larger side opening or port 22 is formed through the wall of cylinder 10. A cover plate 23 preferably of a relatively soft or frangible metal is provided for covering opening 22 and is secured to body member 10 as by screws 24 or other,

suitable means, the cover being suitably curved to conform to the curvature of the body member 10. A cylindrical cup-shaped valve member 25 is longitudinally slidable within body member 10, but is initially supported in the upper portion thereof as shown in Figures la and 1b, by a shear pin 26, the valve having an aperture 27 in the top thereof through which extends a portion of a fuse 35 for the firing of the shaped charge. During the operation of the invention,.as hereinafter more fully described, valve member 25 is released and caused to be moved downwardly to the position shown in Figure 3, so as to close off ports 21. i The shaped-charge cutting unit is indicated generally a 28 and comprises a bell-shaped centrally located supporting element 29 secured at the outer, closed end to-the inner side of cover plate 23 by means of screws 30, andhas an inwardly divergingly flared and flanged portion 31 forming an annular seat for an annular shaped case 32 for the shaped charge explosive. Case 32 is preferably of glass,

porcelain or other suitable ceramic material or of a suitable plastic, and has an outwardly facing,.V-shaped annular cavity 33 for containing theshaped charge explosive material, and also a rearwardly facing annular groove 34. adjacent flange 31 in which is positioned the looped end Patented Mar. .31, 9.

portion of a suitable detonating fuse 35 such as Primacord, the other end portion of which extends, as beforementioned, upwardly through valve port 27 and into head 12. The shaped charge explosive 36 in the annular cavity 33 is formed with anoutwardly directed V-shaped, groove or cavity, the surface of which is covered by a. metallic liner 37 of copper, steel, or the like as is well known in the art. A suitable annular cover 38 is provided for case 32 and is initially held in place by the cover plate 23 and suitably sealed thereto by suitable sealing material, such as, for example, #801 Sealer made by Minnesota Mining and Milling Co.

The cover 38 for the case 32 is dome-shaped in crosssection as shown in Figures 1b and 2 to provide suitable liquid-free stand-off clearance space in front of the shapedcharge 32 and liner 37 and to resist external fluid pressure when the apparatus is lowered into a fluid-filled borehole. Cover 38 is preferably made of glass, porcelain or other suitable ceramic material or of a suitable plastic material or soft metal such as aluminum.

The head member 12 is formed with a cavity 40 adjacent its upper end, which communicates at the lower end thereof with a central, coaxial bore 41 in which is positioned a blasting cap 42 suitably secured to the upper end of the detonating fuse 35. Fuse 35 extends downwardly through bore 41, through a downwardly flared lower portion 41a thereof, and through an opening in a disc 43 suitably seated against a downwardly facing annular shoulder formed in the top end portion of the flared bore 41a and finally through a resilient sealing element 44 which, when forced upwardly into the flared bore against disc 43, forms an effective fluid seal around the fuse 35 and the interior of bore 41a against entrance of fluid from the interior of the body member into the bore 41.

Cable head 14 is formed with an axial bore 45 having an, enlarged lower portion 46 forming at the juncture thereof a downwardly facing annular shoulder 47, portion 46 being internally threaded at 48. Head member 12 is provided with an upwardly facing annular shoulder 49 formed by an enlargement of cavity 40 at the lower end of threads 13. Contained within the axial bore 45, 46 of thte cable head is a plug 50 having an upper portion of reduced diameter, a lower portion of relatively greater diameter joined thereto by an intermediate tapered portion 52. The plug 50 is seated with the reduced upper end portion thereof extending into bore 45 and the enlarged lower portion thereof contained Within bore 46, with the tapered intermediate portion seated against a sealing ring 51, which is in turn seated on shoulder 47. A retainer sleeve 53 is threaded into the lower threaded portion of bore 48, against the lower end of plug 50 and a disc 54 is seated on annular seat 49 and secured there by the lower annular end portion of the cable head 14 which makes threaded engagement with threads 13 of head member 12. Conductor cable contains an insulated electrical conductor 55 which extends from the cable into bore 45 of the cable head and is connected to a conductor pin 56 which extends centrally through and is suitably insulated by an insulating sleeve from plug 50, and a connector or terminal stud 57 is similarly mounted to and extends centrally through disc 54. A conductor spring 58 positioned within sleeve 53 electrically interconnects conductor pin 56 and terminal stud 57. A conductor wire 59 leading from blasting cap 42 is connected to terminal stud 57, and another conductor 60 from the blasting cap is connected to a terminal stud 61 carried by disc 54 and forms a ground connection through the lower end of cable head 14 and the grounded sheath of cable 15.

The cylindrical body member 10 is formed with a side port 62 which is initially closed by a plug 63, which is blown out during the operation of the apparatus as hereinafter described.

As shown in Figures 1b, 2, and 3 the formation of the explosive charges 36 of the shaped charge unit 28 is such as to produce, when detonated, an annularly shaped cutting jet or sheet of gases which converges to form, in efl ect, a hollow cone, the so-called point of convergence or focus of which is substantially at the point indicated at F in Fig. 1b. The action of the annular sheet of gases is such as to produce an annular opening in the surrounding formations of the borehole wall as indicated at A, of progressively reduced diameter laterally from the borehole wall and thereby cut out of the wall of the surrounding formation a substantially cone-shaped sample as shown at C which is ordinarily broken off from the formation at some point such as at D close to the beforementioned focal point P.

In the operation of the invention as thus far described, the sampling tool as shown in Figs. la and lb is lowered into the well bore to the desired position, such as opposite the strata formation illustrated at 20, where the body member 10 is pressed by bow spring 18 against the side wall of the borehole, with cover plate 23 in contact with the formation. Upon the flowing of an electric current through the conductor 55 and through the blasting cap conductors 59 and 60, and thence to ground, the blasting cap is fired, which detonates fuse 35, which in turn detonates the explosive shaped charge 36, and the resultant annular or conical shaped sheet of gases projected from the shaped charge penetrates through the cover plate 23 and out into the formation 20 thereby cutting out and detaching the formation sample C, as hereinbefore described. The firing of the shaped charge creates a pressure within the body member 10 which in case the borehole contains fluid will be filled with liquid, suflicient to dislodge plug 63 from port 62 and to partially expel the liquid from Within said body member 10, through ports 62 and 21. The upward rush of fluids within the body member 10 toward the port 62 shears pin 26, thereby freeing the valve member 25 for longitudinal movement within the body member 10. During the firing of the shaped charge unit, the unit including the annular case 32, cover 38, supporting element 29 and cover plate 23 is substantially disintegrated, and the compressive force remaining in the formation cavity A following the firing of the shaped charge moves the sample C inwardly through opening 22 in the body member 10 permitting the sample to drop down into the lower portion of the body member 10 and onto plug 17, as shown in Fig. 3. The fluid pressure above valve 25 resulting from the return rush of the previously expelled fluid into the top of the body 10, after the shearing of pin 26, causes the valve to drop downwardly closing ofl? ports 21, and enclosing the sample C within the lower portion of the gun body 10, The sampling tool is then removed from the well by reeling in cable 15, and the formation sample C recovered intact.

While the shaped charges are hereinbefore described as being preferably annular in shape or as having an' nular, groove shaped cavities adapted to produce convergingly directed sheets of cutting gases, variations in such shapes may obviously be made. For example the shaped charges or cavities, instead of being truly annular, may be eliptical, oval, polygonal or the like, in shape and produce effective, convergingly directed sheets of cutting gases. Therefore the term annular as used hereinbefore and in the claims shall be considered to include such other suitable shapes as hereinbeforc mentioned.

It is to be understood that the foregoing description is illustrative only, and that the invention is not to be limited thereby, but includes all modifications thereof within the scope of the invention as defined in the uppended claims.

I claim:

1. The combination and apparatus for taking sidewall samples from fluid-filled well boreholes which comprises: a hollow body adapted to be lowered into a borehole and having an opening in the side thereof; explosive shaped charge means within said body so disposed as to project a stream of cutting gases through said opening in the side of said hollow body into an adjacent sidewall, whereby a sample of the material comprising said sidewall may be dislodged therefrom; a chamber in said body located below and in communication with said opening in said hollow body side for receiving and retaining such formation samples entering therethrough; and means releasable upon detonation of said explosive charge to enclose and retain such sample material entering said hollow body through said opening.

2. The combination in apparatus for taking sidewall samples from fluid-filled well boreholes which comprises: a body adapted to be lowered into a borehole and having an opening in the side thereof; explosive shaped charge means within said opening and having a recess therein, said shaped charge recess being so disposed as to direct a stream of cutting gases laterally into an adjacent sidewall, whereby a sample of the material comprising said sidewall may be cut loose therefrom; a chamber in said body located below and in communication with said opening in said body side for receiving and retaining such samples entering therethrough; and means carried by said body and actuatable subsequent to detonation of said explosive charge to enclose and retain such sample material entering said chamber through said opening.

3. The combination in apparatus for taking sidewall samples from fluid-filled well boreholes which comprises: a body adapted to be lowered into a borehole and having an opening in the side thereof; explosive shaped charge means within said opening and having an annular recess therein, said shaped charge annular recess being so disposed as to direct a converging stream of cutting gases laterally into an adjacent sidewall, whereby a generally conical sample of the material comprising said sidewall may be cut loose therefrom; a chamber in said body located below and in communication with said opening in said body side for receiving and retaining formation samples entering therethrough; and means carried by said body and actuatable subsequent to detonation of said explosive charge to enclose and retain such sample material entering said chamber through said opening.

4. The combination and apparatus for taking sidewall samples from fluid-filled well boreholes which comprises; a hollow body adapted to be lowered into a borehole and having an opening in the side thereof; explosive shaped charge means within said body and having an annular recess therein disposed symmetrically about a line normal to said opening in the side of said hollow body, said shaped charge recess being so disposed as to focus a converging stream of cutting gases at a point within the adjacent sidewall, whereby a generally conical sample of material comprising said sidewall may be cut loose therefrom; a chamber in said body located below and in communication with said hollow body side for receiving and retaining formation samples entering therethrough; and means releasable upon detonation of said explosive charge to enclose and retain sample material entering said hollow body through said opening.

5. Apparatus for taking sidewall samples from fluidfilled well boreholes comprising: a hollow body adapted to be lowered into a borehole and having an opening in the side thereof; an explosive shaped charge within said body having an annular groove-shaped cavity therein, said groove-shaped cavity being directed to form an annular-shaped, cutting sheet of gases when said shaped charge is detonated, said sheet of gases converging outside of said hollow body; pressure resistant means for initially excluding borehole liquid from said cavity; means securing said shaped charge within said body and positioned to direct said annular shaped sheet of gases outward through said opening; retaining means initially in communication with said opening for receiving and retaining formation samples entering said opening; and valve means in said body releasable by the detonation of said shaped charge to close at least partially said retaining means from communication with said opening.

6. Apparatus for taking sidewall samples from fluidfilled well boreholes comprising: a body adapted to be lowered into a borehole and having an opening in the side thereof; an explosive shaped charge within said body, having an annular groove-shaped cavity therein, said groove-shaped cavity being directed to form an annular-shaped, cutting sheet of gases when said shaped charge is detonated, converging outside said borehole and defining a definite volume outside said body; pressure resistant means for initially excluding borehole liquid from said cavity; means securing said shaped charge within said opening in position to direct said annular shaped sheet of gases outwardly thereof; retaining means initially in communication with said opening for receiving and retaining formation samples entering said opening; and valve means releasable by the detonation of said shaped charge to close at least partially said retaining means from communication with said opening.

References Cited in the file of this patent UNITED STATES PATENTS 2,307,729 Foster Jan. 5, 1943 2,494,256 Muskat et al J an. 10, 1950 2,587,243 Sweetman Feb. 26, 1952 2,587,244 Sweetman Feb. 26, 1952 2,638,323 Bannon May 12, 1953 

